1. Field of the Invention
The invention relates to an image forming apparatus including a controller configured to control switching to a power saving mode and switching back from the power saving mode.
2. Description of Related Art
An image forming apparatus, or an image forming system, according to the related art includes: a controller configured to convert print data acquired from a host apparatus to which the image forming apparatus is connected through a network, into image data whose image is printable by a print mechanism (engine); and the printer engine is configured to perform a printing process based on the converted image data. The controller includes a central processing unit (CPU), a read only memory (ROM: nonvolatile memory), a random access memory (RAM: volatile memory), a flash memory (nonvolatile memory), a power supply, a circuit configured to detect jobs, and the like. The controller performs various processes by using various programs and data, the programs and data previously being copied from the ROM providing slow access, to the RAM providing fast access, when the apparatus is powered on.
When a job waiting state continues longer than a predetermined time, the various programs and data held by the RAM are copied to the flash memory which provides fast access. After the copying of the programs and data to the flash memory is completed, the power supply continues supplying power only to the circuit configured to detect jobs, while cutting off power to the other units included in the controller, such as the CPU, the ROM, the RAM and the flash memory. Thus, the image forming system is switched to a sleep mode (power saving mode).
Then, in the image forming system, when the circuit detects a job during the power saving mode, the power supply resumes supplying power to the entire controller under the control of the circuit and the CPU starts to operate. Thereafter, upon completion of the copying of the various programs and data held by the flash memory to the RAM, the image forming system is switched back to a normal mode.